In a recently published study, 59 percent of individuals with myasthenia gravis (MG) reported experiencing cognitive difficulties, yet the etiology, severity and extent that these problems impact patients' lives is unknown. In the same study, 89 percent of MG patients complained of fatigue, but it is not clear if fatigue plays an important role in patients' experience of cognitive disturbance, or if psychiatric illness is related to cognitive difficulties in MG. The specific aims of the proposed project are to determine if MG patients experience cognitive deficits compared to healthy control subjects, and to what extent cognitive difficulties in individuals with the disease may be due to disease activity, cognitive and physical fatigue, or psychiatric illness. Further, this study will examine the relationships between cognition, fatigue and mood disturbance and quality of life in individuals with MG. My vision is to utilize an NRSA Fellowship to collect data that will provide critical information relevant to a better understanding of MG symptomatology. I believe that once the status and nature of cognition, fatigue, and psychiatric illness in MG is better understood, appropriate efforts can be directed at providing clinically meaningful intervention.